Your arms are your main tools and when someone takes it away from you, you will fully realize how much you used to take them for granted. This is a world we live in which was crafted for people that had arms. If you do not have arms, you will not be able to get around like the rest of the world does. Luckily a broken arm is only temporary, it is not as if it has been amputated, you will recover.
The main problem though is still the idea that you cannot act. This likely refers to a specific situation where someone has really twisted your arm metaphorically into a position that you can’t get your way out of. Someone has probably gotten you to agree to something that you don’t necessarily agree with and now you are suffering the consequences of it. Perhaps someone has got you into a contract that you want to get out of, but your hands are tied on the matter because of the contract that you have bound yourself into.
There are normally all kinds of different routes for you to take to get yourself out of an unfavorable situation but this time you have dug your hole too deep and now you have to suffer the consequences. To dream that you have a broken arm can also mean that you feel as if you have been lazy about charitable work recently. This is one of the less mainstream interpretations and is one that takes a bit of mental work to think over, but it makes sense when you think about it.
In your dreams, your hands represent your ability to be charitable. They are what you want to extend to help others out of an undesirable situation and arms are known to be attached to hands. If you have a dream in which you literally cannot use your hands because your arm is broken and you are not allowed to exercise those muscles in it then this implies that you feel as if you have cut yourself off from your ability to be charitable. Your lax treatment of this issue is all of your fault and will not show favorably on you, but you are okay with this. You just have not been as charitable as you should lately not even to the most minimal extent that you could.
A dream like this might happen because you feel guilty for not giving a homeless person on the street some of your money when they look particularly desperate. It could also be happening to you because you just haven’t been as charitable lately as you have been in the past. This is also a strong possibility. But the good thing about this is, your guilt is an admission that you are a good soul. Even though you didn’t meet your goals, the fact that you even have goals related to charity shows that you are a good person at heart, assuming that this matters to you in any way.